CA1061952A

CA1061952A - Artificial heart propelled by respiratory muscles

Info

Publication number: CA1061952A
Application number: CA268,715A
Authority: CA
Inventors: Tomasz Cieszynski
Original assignee: Akademia Medyczna
Current assignee: Akademia Medyczna
Priority date: 1975-12-31
Filing date: 1976-12-24
Publication date: 1979-09-11
Also published as: DE2658949C2; DE2658949A1; US4078267A; JPS5284897A; PL104172B1; JPS5620872B2

Abstract

ABSTRACT OF THE DISCLOSURE
The invented artificial heart consists of two ventricles and two atria and is designed for inclusion in a blood circulation system via valves to operate in the same manner as a live heart. The heart is made in the form of a rigid housing containing in its top part two inlet ports and two outlet ports. An elastic ventricle and elastic atrium constitute a symmetrical half of the heart. The bottom part of the housing is shaped in the form of two parallel cylinders capped tightly and slidably with buckets having convex bottoms these bottoms forming pistons. An elastic movable diaphragm is located above each piston, this diaphragm being circumferentially attached to the inside of the cylinder and to the elastic ventricle. Physiological liquid is contained between the ventricle and the diaphragm. The top part of the housing is connected with a branched shank designed for attaching to the human skeleton, and the buckets are attached to the branched elastic, membranaceous and pedate bearer designed to rest against respiratory muscles and their bony lining. The volume of ventricles and of atria in the artificial heart is about four times larger in comparison with that of a live heart. The heart is act-uated by the-motion of respiratory muscles which exert a pressure on the buckets via the bearer, the operation of the heart being similar to that of a hydraulic diaphragm-piston pump.

Description

1~6~g~
This invention presents an artificial heart propelled by respiratory muscles, predominantly by the diaphragm, this heart being designed ~or implan tation into a living human organism in replacement of its own insufficient heart, irreversibly afflicted by lesion.
Disclosed in US Patent No. 3~874,002 issued April 1, 1975 to W.H.
Kurpanek and titled: PULSATILE MAGN~TO-MOTIVE ~RTIFICIAL HE~RT is a magneto~
propelled artificial heart composed of two identical rigid housings. An inlet and an outlet port with two-element valves are provided in the top part of each housing. The top part of the housing, through which the blood flows~

contains two identica]. spaces separated one from the other by a vertical and rigid septum. A one-piece magnetic valve is provided between these spaces, one space playing the role of the atrium, the other that of the ventricle.
This valve is pendulously attached to the top part of the housing. The bottom edge of this valve is set over against the top edge of the vertical septum.
The bottom part of the housing, where a hydraulic pump is contained, is separat-ed from the top part, through which the blood flows, by two elastic bags? these bags being attached at one end to the inner surface of the housing walls, and to the top part of the vertical septum at their other end. The bottom section of the vertical septum is flared, and a rigid partition is attached to this septum~ this partition being horizontal in its mid section and bent at its sides, both ends of this partition being fixed inside the housing. There are ports provided in the bent faces of this rigid partition. A chamber with anti-magnetic screen is contained in the bottom part of the housing. This chamber is filled with liquid and a part of this chamber constitutes a pumping cylinder.
The heart propulsion mechanism is contained in this chamber, this mechanism being composed of a vertically positioned ferromagnetic piston~ the excitation winding of this piston being powered by batteries attached at the housing.
This piston is slidably and elastically mounted on two guiding rods, the ends of these rods being fixed to the two permanent magnets arranged in parallel to ~6:~952 the ferromagnetic piston at both its sides. The poles of the magnets are disposed in opposition one to the other. The length of the moving ~one oE the ferromagnetic piston is the same as that of the horizontal and non-perforated section of the bottom partition. The valves are madle in the form of two-arm magnetic levers swiveling on brackets mounted inside the housing, the longer arms of the levers pointing toward a recess in the wall in which two permanent magnets are installed. One magnet which is antipolar to the valve pole is installed at the blood outlet side near the valve edge while the other magnet which is unipolar with its jointly operating pole of the valve is installed at the blood inlet side, on the extension of the axis of rotation.
The ferromagnetic piston moves in the pumping cylinder, in the space filled with liquid, in reciprocity with the changeover of the polarity of its excitation winding and due to the attraction force of both permanent magnets whose poles are opposed. This motion causes the liquid to flow, once through one and then through the other set of ports provided in the horizontal rigid partition, and from the chamber space to the space below the elastic bags, these bags causing, after being displaced upward by the liquid? the blood to be forced out once from the atrium to the ventricle through the one-piece valve, and then from the ventricle to the blood circulation system, with blood being simultaneously drawn into the atrium. The valves are actuated by the jointly operating permanent magnets. They open under the pressure of Mowing blood which causes the force of both antipoles to be overcome. These antipoles cooperate one with the other when the valves are closed. The valves open under the effect of repulsion of unipolar poles, the pressure of inflowing blood dropping simultaneously.
The disadvantage of the above described artificial heart is the limited capacity of bat*eries which is insufficient for a permanent operation of the heart. Thus the need arises to supply the heart with voltage from external sources, this presenting another imperfection since the winding has ~6~L~5Z
to be supplied with a large current required to overcome the resistance in the hydraulic pump. The principal imperfection inherent in an external power supply for an artificial heart is the danger of infection along the power leads, this presenting a lethal danger for the person carrying such a heart.
Besides, the heart of this type requires an extra analytical and controlling apparatus to control its operation in accordance with the biochemical and physical information obtained on the health condition of the person carrying the heart.
This invention consists of an artificial heart adapted for propulsion by respiratory muscles, this heart comprising two ventricles and two elastic atria. The invented heart is designed for inclusion in the blood circulation -system via closing and opening valves. One ventricle and one atrium of this heart, interconnected by a port with a valve opening at the side of the atrium, constitute one half of the heart, this half being separated from the other half.
The present heart has a rigid housing with a vaulted top part connected with a branched shank and containing elements adjoining the atria and ventricles of the heart, and two inlet and two ports. The bottom part of this housing is shaped in the form of two cylinders situated one beside the other and slidably and tightly capped with two buckets having bottoms convexed towards the inside.
The buckets constitute hollow pistons of the heart which are filled with carbon dioxide. The buckets are attached to a branched elastic membranaceous and pedate bearer, said bearer being adapted to rest against respiratory muscles and their bony lining. An elastic movable diaphragm is situated above each piston, this diaphragm being circumferentially attached to the inner surface of its respective cylinder and also circumferentially to the outer surface of an elastic section of a respective ventricle. Each ventricle has two ports coinciding with the outlet port in the housing and with a port provided in a rigid septum separating the space for each ventricle from that of its respective atrium. A physiological liquid, isotonic relative to the blood and including ~C16195Z
additives consisting of known antithrombotic substances is contained in the space between each movable diaphragm and the respective elastic part of a ventricle. The movable diaphragm is connected with the elastic part of the ventricle. Contained in the space between the piston and movable diaphragm is a liquid of density and viscosity lower than those of` water. There are two ports in each elastic atrium~ said elastic atrium being confined at the top by a part of the housing and at the bottom by the rigid septum. The ports of each atrium coincide wlth the inlet port in the housing and with a port connect-ing the atrium with the ventricle. A pneumatic space contained between each elastic atrium, the part of the housing confining the atrium~ and the septum is filled with carbon dioxide under a pressure lower than that in the space filled with blood. The volume of each ventricle and each atrium is about four times larger than that of an average live heart.
The basic advantage gained from the invented artificial heart is, in comparison with other constructions known in the state of art, that it neither requires a separate power source nor any mechanical connections between the carrying person and power source. In consequence there is no danger of external infection through the wound after the wo~md is healed. This advantage has been obtained because the invented artificial heart is biologically powered by the carrying person himself~ namely by the respiratory muscles. This heart does not require any artificial system controlling its operation since it is automatically controlled by the central nervous system through its respiratory center. The output of the artificial heart is governed by the depth and fre-quency of the breath of the carrying person, thus protecting this person in situations of an increased gas process~ e.gO at an increased pace~ ~hen ascend-ing the stairs, at short running or other more intensive exertion, because a deeper and more frequent breathing results in an increased output of artificial heart. The volume of artificial heart ventricles and atria is about four times larger than that of ventricles and atria of a live heart7 because the physiolo-gical ratio of breath frequency to the beat of heart is about 1 to 4; thus aproper blood circulation is secured suitably to the slow rhythm of artificial heart operation. A smaller thickness of the walls of artificial heart as com-pared with that of a live heart enables the overall dimensions of the former heart to be not markedly increased over those of a live heart in spite of the larger volume of the artificial heart. Slightly larger overall dimensions have in practice no negative effects. An ineffective heart replaced by artificial heart ispa~hologically enlarged in any event. The operation of the artificial heart is biologically controlled by the brain and the spinal bulb where the blood composition analysers are located. These analysers create feedback signals which are sent out to operate respiratory muscles and thus the natural feedback is utilized to power the artificial heart.
A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawingsin which:
Figure I illustrates one half of the heart in a longitudinal section, in the expansion phase of the ventriclej Figure 2 illustrates the same half of the heart in the contraction phase of the ventricle~ and Figure 3 illustrates in an axonometric view the heart housing supported on the heart bearer.
As shown in Figure 3, the new artificial heart consists of two separate halves whose interiors are enclosed by a rigid housing 1, with two inlet ports 2 and two outlet ports 3 provided in the top and vaulted part of the housing. Port~ 2 and 3 of the left half of the heart are designed to be connected with the aorta and with the pulmonary vein to maintain the general circulation in the system of the person carrying the heart, while ports 2 and 3 of the right half of the heart are designed to be connected with the post-and precava and with the pulmonary artery to maintain the lesser circulation, in the same way as in a live heart. Housing 1 is made of epo~y resin bonded fibre glass. The bottom part of the housing is shaped in the form of two cylinders 4 situated one beside the other~ said cylinders being capped with two buckets 5. The edges of buckets 5 and of cylinders ~ are flanged thus protecting these two elements against disconnection after bucket 5 reaches its extreme position of its downward travel. Buckets 5 are provided with conve~
bottoms, these bottoms constituting pistons 6 of the heart. The pistons are hollow in order to reduce their weight and they are filled with carbon dioxide to protect the organism of the heart carryLng person against irreversible gas embolism in the case of a leak. An elastic movable diaphragm 7 is located above each piston 6, this diaphragm being circumferentially attached to the inner surface of cylinder 4. In the top part of the housing, in its mid sec-tion, there are elastic ventricles 8 which are ovoid in their expanded state.
The elastic movable diaphragms 7 are also circumferentially attached to the ventricles~ each diaphrag~ being also attached to a respective bucket 6.
The top part of housing 1 encloses also an elastic atrium 9, the atrium being interconnected with the ventricle 8 via port 10 provided in rigid septum 11. The septum separates the spaces of ventricle 8 and of atrium 9.
The ventricle 8 and atrium 9 are made of polyurethane material. An aqueous solution of physiological salt is contained in a space 12 between the movable elastic diaphragm 7 and the elastic section of ventricle 8, the elastic section being connected with the diaphragm. The solution is isotonic relative to the ; blood and contains heparin. The solution protects the life of the heart carry-ing person in the case of a perforation ta~ing place at the side of ventricle 8 and prevents the inside of the heart from being filled with a thrombosin. A
space 13 between the piston 6 and the movable elastic diaphragm 8 is filled with kerosene to secure a possibly low coefficient of fri¢tion sinca the coefficient of kerosene viscosity is lower than that of water, as well as to reduce the weight of artificial heart since the density of kerosene is lower than that of water. There are two ports in the ventricle 8, said ports coincidlng with the outlet port 3 in the housing and with the port 10 in the rigid septum. Two ports in the elastic atrium 9 coincide with the inlet port 2 in housing 1 and with port 10 connecting the ventricle 8 with atrium 9. Carbon ~ioxide is contained in a pneumatic space 1~ formed between the elastic atrium 9, the rigid elements of housing 1 which contain the atrium~, and the rigid septum 11.
This carbon dioxide is under a pressure lower than that of the blood and pre-vents the irreversibility of embolism should a perforation take place in the elastic atrium 9. Two elastic tubes 15 and 16 made of polyurethane material provide a seal between bucket 5 and cylinder 4, the space between the tubes being filled with kerosene. The inner tube 15 is tightly fitted with its edge to the circumference of piston 6, the other edge being tightly fitted to the inner surface of cylinder 4. The outer tube 16 is tightly fitted with its edge to the circumference of the top part of housing 1, the other edge being tightly fitted over the outer surface of bucket 5. There are valves 17 instal-led in ports 2, 3 and 10 of the heart, said valves being made of two leaves forming a segment of a figure similar to a circle and pointing one to the other with their straight edges. The valves are attached to the walls of ports 2, 3 and 10 by means of their circular edges. Each leaf consists of two layers 18 and 19 of materials of dif~erent elasticity, the material being in the described case polyurethane material. F~ch layer has a different degree oP
polymerization. The layer 18 of material of a higher elasticity is used at the side of blood inflow. The vaulted top part of housing 1 is connected with a branched shank 20 by which the heart is attached to the first ribs of the person carrying the artificial heart. Both cylinders 4 are rigidly fixed to an elastic, branched, membranaceous and pedate bearer 21, said bearer being designed to rest with its membranaceous part 22 against the diaphragm of the person carrying the heart, on the principle of laminar suction. The pedate elements 23 of the bearer are designed to be attached to the eleventh ribs.
The inner faces of the heart which are in contact wi~h blood are :Lined with ~L0619S;2 a smooth layer of artificial endocardium made of materials of negative electric potential relative to a hydrogen electrode, while the outer faces of the heart are lined with a smooth layer of artiEicial pericardium made of materials of zero electric potential relative to a hydrogen electrode.
The invented artificial heart operates on the principle of a bio-logically powered, hydraulic diaphragm-piston type pump. The motion of res-piratory muscles of a person carrying the heart, particularly the motion of the diaphragm~ provides the power for the heart, this power being transmitted via the branched bearer 21 to the buckets 5 sliding on cyllnders 4.
In the compression phase the convex piston 6 moves upward pressing the diaphragm 7, through the physiological liquid, against the elastic ven-tricle 8. The ventricle changes its shape from an ovoid one to that of a flattened crescent and causes the blood to flow out of ventricle 8 and out of the heart. The elastic atrium expands in this phase, the blood flows into the atrium and valve 17 closes the port 10. Valve 17 in inlet port 2 is open, and valve l7 in outlet port 3 is open too.
In the expansion phase the piston 6 moves downward and the elastic diaphragm 7 returns to its previous position. The shape of ventricle 8 changes from that of a flattened crescent to the ovoid one and fills up with blood flowing in from the atrium 9 via part 10 opened by valve 17. Atrium 9 con-tracts in this phase, valve 17 in the inlet port 2 opens and closes in the outlet port 3 thus preventing the blood to return back to the ventricle 8.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An artificial heart adapted for propulsion by respiratory muscles, said heart comprising two ventricles and two elastic atria and being construct-ed for inclusion in a blood circulation system via opening and closing valves, one ventricle and one atrium of said heart interconnected with a port with a valve opening at the side of the atrium, said ventricle and atrium constituting one half of the heart, said half being separated from the other half the said heart, said artificial heart including a rigid housing, the top part of said housing being vaulted and being connected with a branched shank, said top part containing elements adjoining the atria and the ventricles of the heart, two inlet ports and two outlet ports being provided in said top part, the bottom part of said housing being shaped in the form of two cylinders, said cylinders being situated one beside the other and being slidably and tightly capped with two buckets having bottoms convexed towards the inside, said buckets constitut-ing pistons of said heart, said pistons being hollow and filled with carbon dioxide and being attached to a branched elastic, membranaceous and pedate bearer, said bearer being adapted to rest against the respiratory muscles and their bony lining, an elastic movable diaphragm located above each piston, said diaphragm being circumferentially attached to the inner surface of its respective cylinder and being also circumferentially attached to the outer surface of elastic section of a respective ventricle, each ventricle having two ports coinciding with the outlet port in the housing and with a port in a rigid septum, said septum separating the space for each ventricle from that of its respective atrium, a physiological liquid contained in a space between each movable diaphragm and the respective elastic section of a ventricle, said movable diaphragm being connected with said elastic section of ventricle, said liquid being isotonic relative to the blood and containing additives of known antithrombotic substances, a space between each piston and its respective movable diaphragm being filled with a liquid of density and viscosity lower than those of water, each atrium being confined at the top by a part of the housing and by the rigid septum at the bottom and being provided with two ports coinciding with the inlet port in the housing and with a port located between said inlet port in the housing and the ventricle, carbon dioxide being contained in a pneumatic space formed between each elastic atrium, said part of the housing and said septum, said carbon dioxide being under a pressure lower than that in the space filled with blood, the volume of each ventricle and of each atrium being about four times larger than that of an average living heart.

2. An artificial heart as claimed in Claim 1, including valves each composed of two leaves each leaf forming a segment of a figure similar to a circle, said leaves being oriented one to the other with their straight edges and being attached to the walls of respective ports by means of their circular edges, each leaf consisting of two layers of materials having different elasti-city, the layer of material of higher elasticity being installed at the side of blood inflow.

3. An artificial heart as claimed in claim 2, including a seal between each bucket and its respective cylinder made in the form of elastic inner and outer tubes, a liquid of viscosity lower than that of water being contained between said tubes, each inner tube being with its one end circumferentially tightly fitted to its respective piston and with its other end similarly fitted to the inner face of its respective cylinder, and each outer tube being tightly fitted at one end to the top part of the housing and at the other end to the outer face of its respective bucket.

4. An artificial heart as claimed in Claims 1, 2,or 3, wherein the inner faces of the heart which are in contact with blood are lined with a smooth layer of artificial endocardium of a material having negative electric potential relative to a hydrogen electrode.

5. An artificial heart as claimed in Claim 1, 2, or 3, wherein the outer faces of the heart are lined with a smooth layer of artificial pericar-dium of material having a zero electric potential relative to a hydrogen electrode.